A multi-subscription multi-standby communication device may include one or more Subscriber Identity Module (SIM) cards that provide users with access to multiple separate mobile telephony networks. Each SIM may be associated with a different service provider subscription, enabling the multi-subscription multi-standby communication device to communicate with one or more communication networks. Each SIM or subscription may also be associated with a radio access technology (RAT).
A multi-subscription communication device that includes one or more SIMs and connects to two or more separate mobile telephony networks using one or more shared radio frequency (RF) resources/radios may be termed a “multi-standby” communication device. One example of a multi-subscription multi-standby communication device is a dual-SIM-dual-standby (DSDS) communication device, which includes two SIM cards that share a set of radio frequency (RF) circuitry (referred to as an “RF chain” or a “RF resource chain”) to communicate with two separate mobile telephony networks on behalf of their respective subscriptions. Another example is a single-radio LTE (SRLTE) communication device, which includes one SIM card/subscription associated with two (or more) subscriptions that share a single shared RF resource chain to communicate with one or more multi-subscription multi-standby communication networks on behalf of the multiple subscriptions.
At certain times the multiple subscriptions sharing an RF resource chain may need to use the RF resource to communicate with their respective mobile networks simultaneously. Therefore, the communication device may periodically force one subscription to interrupt its RF operations so that another subscription may use the shared RF resource chain to perform communication operations, a process called a “tune-away,” since the RF resource chain must tune away from the frequency bands and/or channels of the first subscription and must tune to frequency bands/channels of the second subscription. As a result of the tune-away, data received using the active subscription may be lost or corrupted and thus difficult or impossible to decode. The problem of data loss during a tune-away is exacerbated when the first subscription is conducting communications that are particularly sensitive to latency or data loss, such as streaming media, for example, eMBMS (Evolved Multimedia Broadcast Multicast Service).